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Maybe majorana fermions could exist but is very different from both quasi particle pair and particle hole pair, it could have both positive and negative charge in superposition until it is being measured, is this possible?

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States with different charges cannot be superposed, because they are in different superselection sectors. This is because charge is a globally conserved quantity.

Consider two states $| \psi_+ \rangle$ and $|\psi_-\rangle$, where the first has a charge of $+1$ and the second of $-1$. Charge conservation implies that

$$\langle \psi_+ |A|\psi_-\rangle = 0$$

for all observables $A$. This means that a system initially in state $| \psi_+ \rangle$ can never be prepared into a superposition of states with $|\psi_- \rangle $, so writing down a state that is a superposition of the two would be physically meaningless.

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